I'm reading the Brothers Karamazov and am still only in Chapter 5 (so don't spoil anything), but I've been fascinated by the discussion about Ecclesiastical Courts and the Separation if Churh and State within Russia and the Church.

I know it is fiction but novels like this often reflect what is going on during the authors lifetime. So what was this debate about over ecclesiastical courts?

I also assume the arguments given in the novel for and against separation of church and state were actual arguments during Dostoevskys lifetime.

One of the profound arguments against it that is given is given by the fictional Fr Paissy who argues that Christ's statement that his "kingdom is not of this world" is used in a different sense than those who argue for separation of church and state use it. Dostoevsky writes, with Fr Paissy saying: "A most unworthy play on words for a churchman! I have read this book to which you objected, and was astonished by this churchman saying 'the Church is a kingdom not of this world.' If it is not of this world, it follows that it cannot exist on earth at all. In the Holy Gospel, the words 'not of this world' are used in a different sense. To play with such words is impossible. Our Lord Jesus Christ came precisely to establish the Church on earth. The Kingdom of Heaven, of course, is not of this world but in heaven, but it is entered in no other way than through the Church that is founded and established on earth. And therefore to make worldly puns in this sense is impossible and unworthy. The Church is indeed a kingdom and appointed to reign, and in the end must undoubtedly be revealed as a kingdom over all the earth - for which we have a covenant ..."

It's funny because earlier, Miusov, I think one of the atheist characters, accuses this line of thinking of being Ultramontanist, to which another hieromonk, Fr Iosif snarkily replies "Ah, but we don't even have mountains!"...

It's just interesting to see that this whole argument has appeared before and that even as Orthodox, we've been arguing over it for the last 200 years at least. Yes, the novel is fiction, but probably reflects what was going on in Russia at the time.